1. Field of the Invention
The invention relates to a broadcast receiver for radio or television signals, particularly a receiver of the portable type or of the mobile built-in type. Such a receiver may be, for example, a portable radio or television set or a car radio.
2. Description of the Prior Art
A broadcast receiver for radio or television signals has a tuning circuit with which the receiver is tuned to a desired broadcast transmitter. In inexpensive sets, this tuning is effected by means of a knob, with a pointer being moved along a frequency scale. More expensive receivers generally have an electronic tuning circuit and a display on which the received frequency is displayed digitally. Moreover, these receivers generally have program keys enabling a user to directly tune to a plurality of preset stations.
Searching of stations and storing preset stations under the program keys, hereinafter referred to as storage procedure, may proceed, for example as follows. After a tuning key is operated, a control circuit in the receiver searches a station having a sufficient signal strength. The user can subsequently store the received station under a selected program key, for example, by operating the relevant program key for at least a given period of time. A tuning value which is characteristic of the received station is stored in response thereto in a storage medium. This operation should be repeated for each available program key. After the storage procedure, the user tunes to a station by operating the relevant program key. The tuning value assigned to this key in the storage medium is then applied to the tuning circuit.
Such a manual storage procedure is time-consuming and often cumbersome. This is not an insurmountable problem when using stationary receivers. However, when using portable receivers which are taken along on, for example, holidays, the storage procedure should be carried out again at every location. The problem is notably manifest in car radios for which the conditions of reception vary continually during long-distance rides.
Therefore, automatic storage procedures as described in Reference [1] are sometimes used in car radios. After a so-called autostore command is generated by the user, the control circuit in the receiver proceeds through an automatic storage program during which stations are uninterruptedly searched and stored under successive program keys until all program keys have been used or no other station with a sufficient signal strength is found any longer. In such an automatic storage procedure, the sequence of storage of the tuning values characteristic of the stations in the storage medium, and hence the sequence of preset stations stored under the successive program keys, is entirely determined by the control circuit. In fact, there is no interaction with the user. For example, a control circuit as described in Reference [1] generates a series of tuning values at an increasing frequency and a decreasing signal strength. The user himself should ascertain and remember which station is stored under which program key. Furthermore, the sequence may be different again after a renewed start of the automatic storage procedure, for example at a different location. This is generally found to be disturbing.
Unwanted stations may be removed by the user. This is notably useful in the case of FM reception in which a given radio program is likely to be transmitted by a plurality of receivable transmitters and is set under more than one program key by means of the automatic storage program. The user then tunes to such an unwanted station by means of the relevant program key and subsequently generates a so-called autoreplace command, for example by operating the relevant program key for a given period of time. The control circuit then searches the next station, which has not yet been preset and subsequently replaces the tuning value of the selected unwanted station in the storage medium by the tuning value of the new station.
Furthermore, a car radio is known which has two selectable memory banks, a first bank for storing manually found tuning values and a second bank for storing automatically found tuning values. Such a combination is very useful, considering that it is now possible to regularly search the locally receivable stations in a simple manner by means of the automatic storage procedure during long car rides and to store them in the second memory bank and, when coming home, to switch back to the first memory bank in which the manually programmed stations are stored in their familiar sequence.